Asymmetrical balloon for intravascular lithotripsy device and method

ABSTRACT

A catheter system for treating a treatment site within or adjacent to a vessel wall within a body of a patient includes an energy source, a balloon, and an energy guide. The energy source generates energy. The balloon includes a balloon wall that defines a balloon interior. The balloon is configured to retain a balloon fluid within the balloon interior. The balloon is selectively inflatable with the balloon fluid to expand to an inflated state, wherein when the balloon is in the inflated state the balloon wall is configured to be positioned substantially adjacent to the treatment site. The balloon further includes a balloon central axis that extends through a geometric center of the balloon when the balloon is in the inflated state. The energy guide selectively receives energy from the energy source and guides the energy from the energy source into the balloon interior. The energy guide including a guide distal end that is positioned on the balloon central axis when the balloon is in the inflated state.

RELATED APPLICATION

This application claims priority on U.S. Provisional Application Ser. No. 62/928,628, filed on Oct. 31, 2019. As far as permitted, the contents of U.S. Provisional Application Ser. No. 62/928,628 are incorporated in their entirety herein by reference.

BACKGROUND

Vascular lesions within vessels in the body can be associated with an increased risk for major adverse events, such as myocardial infarction, embolism, deep vein thrombosis, stroke, and the like. Severe vascular lesions, such as severely calcified vascular lesions, can be difficult to treat and achieve patency for a physician in a clinical setting.

Vascular lesions may be treated using interventions such as drug therapy, balloon angioplasty, atherectomy, stent placement, vascular graft bypass, to name a few. Such interventions may not always be ideal or may require subsequent treatment to address the lesion.

Intravascular lithotripsy is one method that has been recently used with some success for breaking up vascular lesions within vessels in the body. Intravascular lithotripsy utilizes a combination of pressure waves and bubble dynamics that are generated intravascularly in a fluid-filled balloon catheter. In particular, during an intravascular lithotripsy treatment, a high energy source is used to generate plasma and ultimately pressure waves as well as a rapid bubble expansion within a fluid-filled balloon to crack calcification at a lesion site within the vasculature. The associated rapid bubble formation from the plasma initiation and resulting localized fluid velocity within the balloon transfers mechanical energy through the incompressible fluid to impart a fracture force on the intravascular calcium, which is opposed to the balloon wall. The rapid change in fluid momentum upon hitting the balloon wall is known as hydraulic shock, or water hammer.

It is desired to provide more complete plasma formation and bubble formation throughout the balloon interior of the balloon such that a more uniform pressure wave can be applied to the balloon wall in all radial directions, and thus to the vascular lesion at the treatment site. Moreover, it is appreciated that it is an advantage to generate the plasma as far away from the balloon wall as possible to reduce the probability of device malfunctions, such as balloon rupture caused by the high-temperature plasma melting the balloon wall.

There is an ongoing desire to enhance vessel patency and optimization of therapy delivery parameters within an intravascular lithotripsy catheter system.

SUMMARY

The present invention is directed toward a catheter system for placement within a blood vessel having a vessel wall. The catheter system can be used for treating a treatment site within or adjacent to the vessel wall within a body of a patient. In various embodiments, the catheter system includes an energy source, a balloon, and an energy guide. The energy source generates energy. The balloon includes a balloon wall that defines a balloon interior. The balloon is configured to retain a balloon fluid within the balloon interior. The balloon is selectively inflatable with the balloon fluid to expand to an inflated state, wherein when the balloon is in the inflated state the balloon wall is configured to be positioned substantially adjacent to the treatment site. The balloon further includes a balloon central axis that extends through a geometric center of the balloon when the balloon is in the inflated state. The energy guide selectively receives energy from the energy source and guides the energy from the energy source into the balloon interior. The energy guide includes a guide distal end that is positioned on the balloon central axis when the balloon is in the inflated state.

In various embodiments, the balloon is asymmetrical. For example, in such embodiments, the balloon can further include a balloon proximal end, an opposed balloon distal end, and a balloon end axis that extends through the balloon proximal end and the balloon distal end when the balloon is in the inflated state. Additionally, the balloon end axis can be offset from the balloon central axis. In various embodiments, the balloon end axis is spaced apart from and parallel to the balloon central axis.

In certain embodiments, the catheter system further includes a guidewire lumen that extends through the balloon proximal end and the balloon distal end. The guidewire lumen is positioned offset from the balloon central axis. In various embodiments, the guidewire lumen is positioned substantially along the balloon end axis.

In some embodiments, the catheter system further includes a catheter shaft, wherein the balloon is coupled to the catheter shaft. The catheter shaft can include a longitudinal axis. In various embodiments, the longitudinal axis is substantially coaxial with the balloon end axis.

In various embodiments, the energy guide receives the energy from the energy source and guides the energy from the energy source into the balloon interior to generate plasma in the balloon fluid within the balloon interior. In various embodiments, the plasma generation causes rapid bubble formation and impart pressure waves upon the balloon wall adjacent to the treatment site.

In various embodiments, the energy guide can include an optical fiber and/or the energy source is a laser source that provides pulses of laser energy.

The present invention is also directed toward a catheter system for treating a treatment site within or adjacent to a vessel wall within a body of a patient, the catheter system including an energy source that generates energy; an asymmetrical balloon including a balloon wall that defines a balloon interior, the balloon being configured to retain a balloon fluid within the balloon interior, the balloon being selectively inflatable with the balloon fluid to expand to an inflated state, wherein when the balloon is in the inflated state the balloon wall is configured to be positioned substantially adjacent to the treatment site, the balloon further including (i) a balloon proximal end, (ii) an opposed balloon distal end, (iii) a balloon end axis that extends through the balloon proximal end and the balloon distal end when the balloon is in the inflated state, (iv) a balloon central axis that extends through a geometric center of the balloon when the balloon is in the inflated state, the balloon central axis being spaced apart from and substantially parallel to the balloon end axis, and (v) a balloon radius, the balloon central axis being spaced apart from the balloon end axis by an axis spacing distance of at least approximately five percent of the balloon radius; and an energy guide that selectively receives energy from the energy source and guides the energy from the energy source into the balloon interior.

The present invention is also directed toward a catheter system for treating a treatment site within or adjacent to a vessel wall within a body of a patient, the catheter system including an energy source that generates energy; an asymmetrical balloon including a balloon wall that defines a balloon interior, the balloon being configured to retain a balloon fluid within the balloon interior, the balloon being selectively inflatable with the balloon fluid to expand to an inflated state, wherein when the balloon is in the inflated state the balloon wall is configured to be positioned substantially adjacent to the treatment site, the balloon further including (i) a balloon proximal end, (ii) an opposed balloon distal end, (iii) a balloon end axis that extends through the balloon proximal end and the balloon distal end when the balloon is in the inflated state, and (iv) a balloon central axis that extends through a geometric center of the balloon when the balloon is in the inflated state, the balloon central axis being spaced apart from and substantially parallel to the balloon end axis; a guidewire lumen that extends at least between the balloon proximal end and the balloon distal end, the guidewire lumen being positioned substantially along the balloon end axis and offset from the balloon central axis; a catheter shaft including a longitudinal axis that is substantially coaxial with the balloon end axis, the balloon being coupled to the catheter shaft; and an energy guide that selectively receives energy from the energy source and guides the energy from the energy source into the balloon interior to generate plasma in the balloon fluid within the balloon interior, the plasma generation causing rapid bubble formation and imparting pressure waves upon the balloon wall adjacent to the treatment site, the energy guide including a guide distal end that is positioned on the balloon central axis when the balloon is in the inflated state.

This summary is an overview of some of the teachings of the present application and is not intended to be an exclusive or exhaustive treatment of the present subject matter. Further details are found in the detailed description and appended claims. Other aspects will be apparent to persons skilled in the art upon reading and understanding the following detailed description and viewing the drawings that form a part thereof, each of which is not to be taken in a limiting sense. The scope herein is defined by the appended claims and their legal equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:

FIG. 1 is a schematic cross-sectional view of an embodiment of a catheter system in accordance with various embodiments;

FIG. 2A is a schematic cross-sectional view of a portion of an embodiment of the catheter system;

FIG. 2B is a schematic cross-sectional view of the portion of the catheter system taken on line B-B in FIG. 2A;

FIG. 2C is a schematic cross-sectional view of the portion of the catheter system taken on line C-C in FIG. 2A; and

FIG. 3 is a schematic cross-sectional view of a portion of another embodiment of the catheter system.

While embodiments of the present invention are susceptible to various modifications and alternative forms, specifics thereof have been shown by way of example and drawings, and are described in detail herein. It is understood, however, that the scope herein is not limited to the particular embodiments described. On the contrary, the intention is to cover modifications, equivalents, and alternatives falling within the spirit and scope herein.

DESCRIPTION

Treatment of vascular lesions can reduce major adverse events or death in affected subjects. As referred to herein, a major adverse event is one that can occur anywhere within the body due to the presence of a vascular lesion. Major adverse events can include, but are not limited to, major adverse cardiac events, major adverse events in the peripheral or central vasculature, major adverse events in the brain, major adverse events in the musculature, or major adverse events in any of the internal organs.

The catheter systems and related methods disclosed herein are configured to impart pressure waves to induce fractures in a treatment site, such as a calcified vascular lesion or a fibrous vascular lesion, within or adjacent a blood vessel wall. In particular, the catheter systems can include a catheter configured to advance to the treatment site located within or adjacent a blood vessel within a body of a patient. The catheter includes a catheter shaft, and an inflatable balloon that is coupled and/or secured to the catheter shaft. The balloons can include a balloon wall that defines a balloon interior. The balloons can be configured to receive a balloon fluid within the balloon interior to expand from a deflated state suitable for advancing the catheter through a patient's vasculature, to an inflated state suitable for anchoring the catheter in position relative to the treatment site.

Additionally, in various embodiments, the catheter systems and related methods utilize an energy source, i.e. a light source such as a laser source or another suitable energy source, which provides energy that is guided by one or more energy guides, e.g., light guides such as optical fibers, which are disposed along the catheter shaft and within the balloon interior of the balloon to create a localized plasma in the balloon fluid that is retained within the balloon interior of the balloon. As such, the energy guide can sometimes be referred to as, or can be said to incorporate a “plasma generator” at or near a guide distal end of the energy guide that is positioned within the balloon interior of the balloon located at the treatment site. The creation of the localized plasma can initiate a pressure wave and can initiate the rapid formation of one or more bubbles that can rapidly expand to a maximum size and then dissipate through a cavitation event that can launch a pressure wave upon collapse. The rapid expansion of the plasma-induced bubbles can generate one or more pressure waves within the balloon fluid retained within the balloon interior of the balloon and thereby impart pressure waves onto and induce fractures in the treatment site at the treatment site within or adjacent to the blood vessel wall within the body of the patient. In some embodiments, the energy source can be configured to provide sub-millisecond pulses of energy, e.g., light energy, to initiate the plasma formation in the balloon fluid within the balloon to cause the rapid bubble formation and to impart the pressure waves upon the balloon wall at the treatment site. Thus, the pressure waves can transfer mechanical energy through an incompressible balloon fluid to the treatment site to impart a fracture force on the intravascular lesion. Without wishing to be bound by any particular theory, it is believed that the rapid change in balloon fluid momentum upon the balloon wall that is in contact with the intravascular lesion is transferred to the intravascular lesion to induce fractures to the lesion.

As used herein, the terms “intravascular lesion” and “vascular lesion” are used interchangeably unless otherwise noted. As such, the intravascular lesions and/or the vascular lesions are sometimes referred to herein simply as “lesions”.

Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings. The same or similar nomenclature and/or reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts.

In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It is appreciated that in the development of any such actual implementation, numerous implementation-specific decisions must be made in order to achieve the developer's specific goals, such as compliance with application-related and business-related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it is recognized that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

It is also appreciated that the catheter systems disclosed herein can include many different forms. Referring now to FIG. 1 , a schematic cross-sectional view is shown of a catheter system 100 in accordance with various embodiments. The catheter system 100 is suitable for imparting pressure waves to induce fractures in one or more treatment sites within or adjacent a vessel wall of a blood vessel. In the embodiment illustrated in FIG. 1 , the catheter system 100 can include one or more of a catheter 102, an energy guide bundle 122 including one or more energy guides 122A, a source manifold 136, a fluid pump 138, a system console 123 including one or more of an energy source 124, a power source 125, a system controller 126, and a graphic user interface 127 (a “GUI”), and a handle assembly 128. Alternatively, the catheter system 100 can have more components or fewer components than those specifically illustrated and described in relation to FIG. 1 .

The catheter 102 is configured to move to a treatment site 106 within or adjacent to a vessel wall 108A of a blood vessel 108 within a body 107 of a patient 109. The treatment site 106 can include one or more vascular lesions 106A such as calcified vascular lesions, for example. Additionally, or in the alternative, the treatment site 106 can include vascular lesions 106A such as fibrous vascular lesions.

The catheter 102 can include an inflatable balloon 104 (sometimes referred to herein simply as a “balloon”), a catheter shaft 110 and a guidewire 112. The balloon 104 can be coupled to the catheter shaft 110. The balloon 104 can include a balloon proximal end 104P and a balloon distal end 104D. The catheter shaft 110 can extend from a proximal portion 114 of the catheter system 100 to a distal portion 116 of the catheter system 100. The catheter shaft 110 can include a longitudinal axis 144. The catheter shaft 110 can also include a guidewire lumen 118 which is configured to move over the guidewire 112. As utilized herein, the guidewire lumen 118 defines a conduit through which the guidewire 112 extends. The catheter shaft 110 can further include an inflation lumen (not shown) and/or various other lumens for various other purposes. In some embodiments, the catheter 102 can have a distal end opening 120 and can accommodate and be tracked over the guidewire 112 as the catheter 102 is moved and positioned at or near the treatment site 106.

The balloon 104 includes a balloon wall 130 that defines a balloon interior 146. The balloon 104 can be selectively inflated with a balloon fluid 132 to expand from a deflated state suitable for advancing the catheter 102 through a patient's vasculature, to an inflated state (as shown in FIG. 1 ) suitable for anchoring the catheter 102 in position relative to the treatment site 106. Stated in another manner, when the balloon 104 is in the inflated state, the balloon wall 130 of the balloon 104 is configured to be positioned substantially adjacent to the treatment site 106. It is appreciated that although FIG. 1 illustrates the balloon wall 130 of the balloon 104 being shown spaced apart from the treatment site 106 of the blood vessel 108 when in the inflated state, this is done for ease of illustration. It is recognized that the balloon wall 130 of the balloon 104 will typically be substantially directly adjacent to and/or abutting the treatment site 106 when the balloon 104 is in the inflated state.

The balloon 104 suitable for use in the catheter system 100 includes those that can be passed through the vasculature of a patient when in the deflated state. In some embodiments, the balloons 104 are made from silicone. In other embodiments, the balloon 104 can be made from materials such as polydimethylsiloxane (PDMS), polyurethane, polymers such as PEBAX™ material, nylon, or any other suitable material.

The balloon 104 can have any suitable diameter (in the inflated state). In various embodiments, the balloon 104 can have a diameter (in the inflated state) ranging from less than one millimeter (mm) up to 25 mm. In some embodiments, the balloon 104 can have a diameter (in the inflated state) ranging from at least 1.5 mm up to 14 mm. In some embodiments, the balloon 104 can have a diameter (in the inflated state) ranging from at least two mm up to five mm.

In some embodiments, the balloon 104 can have a length ranging from at least three mm to 300 mm. More particularly, in some embodiments, the balloon 104 can have a length ranging from at least eight mm to 200 mm. It is appreciated that a balloon 104 having a relatively longer length can be positioned adjacent to larger treatment sites 106, and, thus, may be usable for imparting pressure waves onto and inducing fractures in larger vascular lesions 106A or multiple vascular lesions 106A at precise locations within the treatment site 106. It is further appreciated that a longer balloon 104 can also be positioned adjacent to multiple treatment sites 106 at any one given time.

The balloon 104 can be inflated to inflation pressures of between approximately one atmosphere (atm) and 70 atm. In some embodiments, the balloon 104 can be inflated to inflation pressures of from at least 20 atm to 60 atm. In other embodiments, the balloon 104 can be inflated to inflation pressures of from at least six atm to 20 atm. In still other embodiments, the balloon 104 can be inflated to inflation pressures of from at least three atm to 20 atm. In yet other embodiments, the balloon 104 can be inflated to inflation pressures of from at least two atm to ten atm.

The balloon 104 can have various shapes, including, but not to be limited to, a conical shape, a square shape, a rectangular shape, a spherical shape, a conical/square shape, a conical/spherical shape, an extended spherical shape, an oval shape, a tapered shape, a bone shape, a stepped diameter shape, an offset shape, or a conical offset shape. In some embodiments, the balloon 104 can include a drug eluting coating or a drug eluting stent structure. The drug eluting coating or drug eluting stent can include one or more therapeutic agents including anti-inflammatory agents, anti-neoplastic agents, anti-angiogenic agents, and the like.

As described in greater detail below, the balloon 104 can include a balloon central axis 260 (illustrated in FIG. 2A) when the balloon 104 is in the inflated state. During use of the catheter system 100, such as when the balloon 104 is in the inflated state and while pulses of energy are being provided by the energy source 124, at least a portion of one of the one or more energy guides 122A, including a guide distal end 122D of such energy guide 122A which effectively serves as a point of plasma generation, is positioned on the balloon central axis 260. With this design, more complete plasma formation and bubble formation can occur throughout the balloon interior 146 of the balloon 104 because the guide distal end 122D of the energy guide 122A from which the plasma is generated can be positioned substantially equidistant from the balloon wall 130 around an entire circumference of the balloon 104. Further, with the guide distal end 122D of one of the energy guides 122A being positioned on the balloon central axis 260, a more uniform pressure wave can be applied to the balloon wall 130, and thus to the vascular lesion 106A at the treatment site 106, since the guide distal end 122D of the energy guide 122A is positioned substantially equidistant from the balloon wall 130 around the entire circumference of the balloon 104. The plasma generation occurring more uniformly and farther away relative to the balloon wall 130 can reduce the likelihood of device malfunction, such as rupture of the balloon 104 caused by the high-temperature plasma melting the balloon wall 130.

In various embodiments, at least the guide distal end 122D of the energy guide 122A can be positioned on or near the balloon central axis 260 (in the inflated state) by offsetting the guidewire lumen 118 from the balloon central axis 260. In various embodiments, offsetting the guidewire lumen 118 from the balloon central axis 260 is achieved by deliberately forming an asymmetric balloon shape, where the balloon ends 104P, 104D define a balloon end axis 262 (illustrated in FIG. 2A) that is different than and/or offset from the balloon central axis 260 of the inflated balloon 104, and positioning the guidewire lumen 118 along or about the balloon end axis 262.

The balloon fluid 132 can be a liquid or a gas. Some examples of the balloon fluid 132 suitable for use can include, but are not limited to one or more of water, saline, contrast medium, fluorocarbons, perfluorocarbons, gases, such as carbon dioxide, or any other suitable balloon fluid 132. In some embodiments, the balloon fluid 132 can be used as a base inflation fluid. In some embodiments, the balloon fluid 132 can include a mixture of saline to contrast medium in a volume ratio of approximately 50:50. In other embodiments, the balloon fluid 132 include a mixture of saline to contrast medium in a volume ratio of approximately 25:75. In still other embodiments, the balloon fluid 132 include a mixture of saline to contrast medium in a volume ratio of approximately 75:25. However, it is understood that any suitable ratio of saline to contrast medium can be used. The balloon fluid 132 can be tailored on the basis of composition, viscosity, and the like so that the rate of travel of the pressure waves are appropriately manipulated. In certain embodiments, the balloon fluids 132 suitable for use are biocompatible. A volume of balloon fluid 132 can be tailored by the chosen energy source 124 and the type of balloon fluid 132 used.

In some embodiments, the contrast agents used in the contrast media can include, but are not to be limited to, iodine-based contrast agents, such as ionic or non-ionic iodine-based contrast agents. Some non-limiting examples of ionic iodine-based contrast agents include diatrizoate, metrizoate, iothalamate, and ioxaglate. Some non-limiting examples of non-ionic iodine-based contrast agents include iopamidol, iohexol, ioxilan, iopromide, iodixanol, and ioversol. In other embodiments, non-iodine based contrast agents can be used. Suitable non-iodine containing contrast agents can include gadolinium (III)-based contrast agents. Suitable fluorocarbon and perfluorocarbon agents can include, but are not to be limited to, agents such as the perfluorocarbon dodecafluoropentane (DDFP, C5F12).

The balloon fluids 132 can include those that include absorptive agents that can selectively absorb light in the ultraviolet region (e.g., at least ten nanometers (nm) to 400 nm), the visible region (e.g., at least 400 nm to 780 nm), or the near-infrared region (e.g., at least 780 nm to 2.5 μm) of the electromagnetic spectrum. Suitable absorptive agents can include those with absorption maxima along the spectrum from at least ten nm to 2.5 μm. Alternatively, the balloon fluids 132 can include those that include absorptive agents that can selectively absorb light in the mid-infrared region (e.g., at least 2.5 μm to 15 μm), or the far-infrared region (e.g., at least 15 μm to one mm) of the electromagnetic spectrum. In various embodiments, the absorptive agent can be those that have an absorption maximum matched with the emission maximum of the laser used in the catheter system 100. By way of non-limiting examples, various lasers uable in the catheter system 100 can include neodymium:yttrium-aluminum-garnet (Nd:YAG−emission maximum=1064 nm) lasers, holmium:YAG (Ho:YAG−emission maximum=2.1 μm) lasers, or erbium:YAG (Er:YAG−emission maximum=2.94 μm) lasers. In some embodiments, the absorptive agents can be water soluble. In other embodiments, the absorptive agents are not water soluble. In some embodiments, the absorptive agents used in the balloon fluids 132 can be tailored to match the peak emission of the energy source 124. Various energy sources 124 having emission wavelengths of at least ten nanometers to one millimeter are discussed elsewhere herein.

The catheter shaft 110 of the catheter 102 can be coupled to the one or more energy guides 122A of the energy guide bundle 122 that are in optical communication with the energy source 124. The energy guide(s) 122A can be disposed along the catheter shaft 110 and within the balloon 104. In some embodiments, each energy guide 122A can be an optical fiber and the energy source 124 can be a laser. The energy source 124 can be in optical communication with the energy guides 122A at the proximal portion 114 of the catheter system 100.

In some embodiments, the catheter shaft 110 can be coupled to multiple energy guides 122A such as a first energy guide, a second energy guide, a third energy guide, etc., which can be disposed at any suitable positions about the guidewire lumen 118 and/or the catheter shaft 110. For example, in certain non-exclusive embodiments, two energy guides 122A can be spaced apart by approximately 180 degrees about the circumference of the guidewire lumen 118 and/or the catheter shaft 110; three energy guides 122A can be spaced apart by approximately 120 degrees about the circumference of the guidewire lumen 118 and/or the catheter shaft 110; or four energy guides 122A can be spaced apart by approximately 90 degrees about the circumference of the guidewire lumen 118 and/or the catheter shaft 110. Still alternatively, multiple energy guides 122A need not be uniformly spaced apart from one another about the circumference of the guidewire lumen 118 and/or the catheter shaft 110. More particularly, it is further appreciated that the energy guides 122A can be disposed uniformly or non-uniformly about the guidewire lumen 118 and/or the catheter shaft 110 to achieve the desired effect in the desired locations.

It is appreciated that the catheter system 100 and/or the energy guide bundle 122 can include any number of energy guides 122A in optical communication with the energy source 124 at the proximal portion 114, and with the balloon fluid 132 within the balloon interior 146 of the balloon 104 at the distal portion 116. For example, in some embodiments, the catheter system 100 and/or the energy guide bundle 122 can include from one energy guide 122A to greater than 30 energy guides 122A. However, regardless of the total number of energy guides 122A, at least the guide distal end 122D of one of the energy guides 122A is positioned on the balloon central axis 260 during use of the catheter system 100.

It is appreciated that the energy guides 122A can have any suitable design for purposes of generating plasma and/or pressure waves in the balloon fluid 132 within the balloon interior 146. Thus, the general description of the energy guides 122A as light guides is not intended to be limiting in any manner, except for as set forth in the claims appended hereto. More particularly, it is appreciated that although the catheter systems 100 illustrated herein are often described with the energy source 124 as a light source and the one or more energy guides 122A as light guides, the catheter system 100 can alternatively include any suitable energy source 124 and energy guides 122A for purposes of generating the desired plasma in the balloon fluid 132 within the balloon interior 146. For example, in one non-exclusive alternative embodiment, the energy source 124 can be configured to provide high voltage pulses, and each energy guide 122A can include an electrode pair including spaced apart electrodes that extend into the balloon interior 146. In such embodiment, each pulse of high voltage is applied to the electrodes and forms an electrical arc across the electrodes, which, in turn, generates the plasma and forms the pressure waves within the balloon fluid 132 that are utilized to provide the fracture force onto the vascular lesions 106A at the treatment site 106. Still alternatively, the energy source 124 and/or the energy guides 122A can have another suitable design and/or configuration.

In certain embodiments, the energy guides 122A can include an optical fiber or flexible light pipe. The energy guides 122A can be thin and flexible and can allow light signals to be sent with very little loss of strength. The energy guides 122A can include a core surrounded by a cladding about its circumference. In some embodiments, the core can be a cylindrical core or a partially cylindrical core. The core and cladding of the energy guides 122A can be formed from one or more materials, including but not limited to one or more types of glass, silica, or one or more polymers. The energy guides 122A may also include a protective coating, such as a polymer. It is appreciated that the index of refraction of the core will be greater than the index of refraction of the cladding.

Each energy guide 122A can guide energy along its length from a guide proximal end 122P to the guide distal end 122D having at least one optical window (not shown) that is positioned within the balloon interior 146.

The energy guides 122A can assume many configurations about and/or relative to the catheter shaft 110 of the catheter 102. In some embodiments, the energy guides 122A can run parallel to the longitudinal axis 144 of the catheter shaft 110. In some embodiments, the energy guides 122A can be physically coupled to the catheter shaft 110. In other embodiments, the energy guides 122A can be disposed along a length of an outer diameter of the catheter shaft 110. In yet other embodiments, the energy guides 122A can be disposed within one or more energy guide lumens within the catheter shaft 110.

It is further appreciated that the energy guides 122A can be disposed at any suitable positions about the circumference of the guidewire lumen 118 and/or the catheter shaft 110, and the guide distal end 122D of each of the energy guides 122A can be disposed at any suitable longitudinal position relative to the length of the balloon 104 and/or relative to the length of the guidewire lumen 118.

In certain embodiments, the energy guides 122A can include one or more photoacoustic transducers 154, where each photoacoustic transducer 154 can be in optical communication with the energy guide 122A within which it is disposed. In some embodiments, the photoacoustic transducers 154 can be in optical communication with the guide distal end 122D of the energy guide 122A. Additionally, in such embodiments, the photoacoustic transducers 154 can have a shape that corresponds with and/or conforms to the guide distal end 122D of the energy guide 122A.

The photoacoustic transducer 154 is configured to convert light energy into an acoustic wave at or near the guide distal end 122D of the energy guide 122A. It is appreciated that the direction of the acoustic wave can be tailored by changing an angle of the guide distal end 122D of the energy guide 122A.

It is further appreciated that the photoacoustic transducers 154 disposed at the guide distal end 122D of the energy guide 122A can assume the same shape as the guide distal end 122D of the energy guide 122A. For example, in certain non-exclusive embodiments, the photoacoustic transducer 154 and/or the guide distal end 122D can have a conical shape, a convex shape, a concave shape, a bulbous shape, a square shape, a stepped shape, a half-circle shape, an ovoid shape, and the like. It is also appreciated that the energy guide 122A can further include additional photoacoustic transducers 154 disposed along one or more side surfaces of the length of the energy guide 122A.

The energy guides 122A can further include one or more diverting features or “diverters” (not shown in FIG. 1 ) within the energy guide 122A that are configured to direct energy to exit the energy guide 122A toward a side surface which can be located at or near the guide distal end 122D of the energy guide 122A, and toward the balloon wall 130. A diverting feature can include any feature of the system that diverts energy from the energy guide 122A away from its axial path toward a side surface of the energy guide 122A. Additionally, the energy guides 122A can each include one or more optical windows disposed along the longitudinal or circumferential surfaces of each energy guide 122A and in optical communication with a diverting feature. Stated in another manner, the diverting features can be configured to direct energy in the energy guide 122A toward a side surface that is at or near the guide distal end 122D, where the side surface is in optical communication with an optical window. The optical windows can include a portion of the energy guide 122A that allows energy to exit the energy guide 122A from within the energy guide 122A, such as a portion of the energy guide 122A lacking a cladding material on or about the energy guide 122A.

Examples of the diverting features suitable for use include a reflecting element, a refracting element, and a fiber diffuser. The diverting features suitable for focusing energy away from the tip of the energy guides 122A can include, but are not to be limited to, those having a convex surface, a gradient-index (GRIN) lens, and a mirror focus lens. Upon contact with the diverting feature, the energy is diverted within the energy guide 122A to one or more of a plasma generator 133 and the photoacoustic transducer 154 that is in optical communication with a side surface of the energy guide 122A. The photoacoustic transducer 154 then converts light energy into an acoustic wave that extends away from the side surface of the energy guide 122A.

The source manifold 136 can be positioned at or near the proximal portion 114 of the catheter system 100. The source manifold 136 can include one or more proximal end openings that can receive the one or more energy guides 122A of the energy guide bundle 122, the guidewire 112, and/or an inflation conduit 140 that is coupled in fluid communication with the fluid pump 138. The catheter system 100 can also include the fluid pump 138 that is configured to inflate the balloon 104 with the balloon fluid 132, i.e. via the inflation conduit 140, as needed.

As noted above, in the embodiment illustrated in FIG. 1 , the system console 123 includes one or more of the energy source 124, the power source 125, the system controller 126, and the GUI 127. Alternatively, the system console 123 can include more components or fewer components than those specifically illustrated in FIG. 1 . For example, in certain non-exclusive alternative embodiments, the system console 123 can be designed without the GUI 127. Still alternatively, one or more of the energy source 124, the power source 125, the system controller 126, and the GUI 127 can be provided within the catheter system 100 without the specific need for the system console 123.

As shown, the system console 123, and the components included therewith, is operatively coupled to the catheter 102, the energy guide bundle 122, and the remainder of the catheter system 100. For example, in some embodiments, as illustrated in FIG. 1 , the system console 123 can include a console connection aperture 148 (also sometimes referred to generally as a “socket”) by which the energy guide bundle 122 is mechanically coupled to the system console 123. In such embodiments, the energy guide bundle 122 can include a guide coupling housing 150 (also sometimes referred to generally as a “ferrule”) that houses a portion, e.g., the guide proximal end 122P, of each of the energy guides 122A. The guide coupling housing 150 is configured to fit and be selectively retained within the console connection aperture 148 to provide the mechanical coupling between the energy guide bundle 122 and the system console 123.

The energy guide bundle 122 can also include a guide bundler 152 (or “shell”) that brings each of the individual energy guides 122A closer together so that the energy guides 122A and/or the energy guide bundle 122 can be in a more compact form as it extends with the catheter 102 into the blood vessel 108 during use of the catheter system 100.

The energy source 124 can be selectively and/or alternatively coupled in optical communication with each of the energy guides 122A, i.e. to the guide proximal end 122P of each of the energy guides 122A, in the energy guide bundle 122. In particular, the energy source 124 is configured to generate energy in the form of a source beam 124A, such as a pulsed source beam, that can be selectively and/or alternatively directed to and received by each of the energy guides 122A in the energy guide bundle 122 as an individual guide beam 124B. Alternatively, the catheter system 100 can include more than one energy source 124. For example, in one non-exclusive alternative embodiment, the catheter system 100 can include a separate energy source 124 for each of the energy guides 122A in the energy guide bundle 122.

The energy source 124 can have any suitable design. In certain embodiments, the energy source 124 can be configured to provide sub-millisecond pulses of energy from the energy source 124 that are focused onto a small spot in order to couple it into the guide proximal end 122P of the energy guide 122A. Such pulses of energy are then directed and/or guided along the energy guides 122A to a location within the balloon interior 146 of the balloon 104, thereby inducing plasma formation in the balloon fluid 132 within the balloon interior 146 of the balloon 104, e.g., via the plasma generator 133 that can be located at the guide distal end 122D of the energy guide 122A. In particular, the energy emitted at the guide distal end 122D of the energy guide 122A energizes the plasma generator 133 to form the plasma within the balloon fluid 132 within the balloon interior 146. The plasma formation causes rapid bubble formation, and imparts pressure waves upon the treatment site 106. An exemplary plasma-induced bubble 134 is illustrated in FIG. 1 .

In various non-exclusive alternative embodiments, the sub-millisecond pulses of energy from the energy source 124 can be delivered to the treatment site 106 at a frequency of between approximately one hertz (Hz) and 5000 Hz, approximately 30 Hz and 1000 Hz, approximately ten Hz and 100 Hz, or approximately one Hz and 30 Hz. Alternatively, the sub-millisecond pulses of energy can be delivered to the treatment site 106 at a frequency that can be greater than 5000 Hz or less than one Hz, or any other suitable range of frequencies.

It is appreciated that although the energy source 124 is typically utilized to provide pulses of energy, the energy source 124 can still be described as providing a single source beam 124A, i.e. a single pulsed source beam.

The energy sources 124 suitable for use can include various types of light sources including lasers and lamps. Alternatively, the energy sources 124 can include any suitable type of energy source.

Suitable lasers can include short pulse lasers on the sub-millisecond timescale. In some embodiments, the energy source 124 can include lasers on the nanosecond (ns) timescale. The lasers can also include short pulse lasers on the picosecond (ps), femtosecond (fs), and microsecond (us) timescales. It is appreciated that there are many combinations of laser wavelengths, pulse widths and energy levels that can be employed to achieve plasma in the balloon fluid 132 of the catheter 102. In various non-exclusive alternative embodiments, the pulse widths can include those falling within a range including from at least ten ns to 3000 ns, at least 20 ns to 100 ns, or at least one ns to 500 ns. Alternatively, any other suitable pulse width range can be used.

Exemplary nanosecond lasers can include those within the UV to IR spectrum, spanning wavelengths of about ten nanometers (nm) to one millimeter (mm). In some embodiments, the energy sources 124 suitable for use in the catheter systems 100 can include those capable of producing light at wavelengths of from at least 750 nm to 2000 nm. In other embodiments, the energy sources 124 can include those capable of producing light at wavelengths of from at least 700 nm to 3000 nm. In still other embodiments, the energy sources 124 can include those capable of producing light at wavelengths of from at least 100 nm to ten micrometers (μm). Nanosecond lasers can include those having repetition rates of up to 200 kHz. In some embodiments, the laser can include a Q-switched thulium:yttrium-aluminum-garnet (Tm:YAG) laser. In other embodiments, the laser can include a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser, holmium:yttrium-aluminum-garnet (Ho:YAG) laser, erbium:yttrium-aluminum-garnet (Er:YAG) laser, excimer laser, helium-neon laser, carbon dioxide laser, as well as doped, pulsed, fiber lasers.

The catheter system 100 can generate pressure waves having maximum pressures in the range of at least one megapascal (MPa) to 100 MPa. The maximum pressure generated by a particular catheter system 100 will depend on the energy source 124, the absorbing material, the bubble expansion, the propagation medium, the balloon material, and other factors. In various non-exclusive alternative embodiments, the catheter systems 100 can generate pressure waves having maximum pressures in the range of at least approximately two MPa to 50 MPa, at least approximately two MPa to 30 MPa, or approximately at least 15 MPa to 25 MPa.

The pressure waves can be imparted upon the treatment site 106 from a distance within a range from at least approximately 0.1 millimeters (mm) to greater than approximately 25 mm extending radially from the energy guides 122A when the catheter 102 is placed at the treatment site 106. In various non-exclusive alternative embodiments, the pressure waves can be imparted upon the treatment site 106 from a distance within a range from at least approximately ten mm to 20 mm, at least approximately one mm to ten mm, at least approximately 1.5 mm to four mm, or at least approximately 0.1 mm to ten mm extending radially from the energy guides 122A when the catheter 102 is placed at the treatment site 106. In other embodiments, the pressure waves can be imparted upon the treatment site 106 from another suitable distance that is different than the foregoing ranges. In some embodiments, the pressure waves can be imparted upon the treatment site 106 within a range of at least approximately two MPa to 30 MPa at a distance from at least approximately 0.1 mm to ten mm. In some embodiments, the pressure waves can be imparted upon the treatment site 106 from a range of at least approximately two MPa to 25 MPa at a distance from at least approximately 0.1 mm to ten mm. Still alternatively, other suitable pressure ranges and distances can be used.

The power source 125 is electrically coupled to and is configured to provide necessary power to each of the energy source 124, the system controller 126, the GUI 127, and the handle assembly 128. The power source 125 can have any suitable design for such purposes.

The system controller 126 is electrically coupled to and receives power from the power source 125. Additionally, the system controller 126 is coupled to and is configured to control operation of each of the energy source 124 and the GUI 127. The system controller 126 can include one or more processors or circuits for purposes of controlling the operation of at least the energy source 124 and the GUI 127. For example, the system controller 126 can control the energy source 124 for generating pulses of energy as desired and/or at any desired firing rate.

The system controller 126 can further be configured to control operation of other components of the catheter system 100 such as the positioning of the catheter 102 adjacent to the treatment site 106, the inflation of the balloon 104 with the balloon fluid 132, etc. Further, or in the alternative, the catheter system 100 can include one or more additional controllers that can be positioned in any suitable manner for purposes of controlling the various operations of the catheter system 100. For example, in certain embodiments, an additional controller and/or a portion of the system controller 126 can be positioned and/or incorporated within the handle assembly 128.

The GUI 127 is accessible by the user or operator of the catheter system 100. Additionally, the GUI 127 is electrically connected to the system controller 126. With such design, the GUI 127 can be used by the user or operator to ensure that the catheter system 100 is effectively utilized to impart pressure onto and induce fractures into the vascular lesions 106A at the treatment site 106. The GUI 127 can provide the user or operator with information that can be used before, during and after use of the catheter system 100. In one embodiment, the GUI 127 can provide static visual data and/or information to the user or operator. In addition, or in the alternative, the GUI 127 can provide dynamic visual data and/or information to the user or operator, such as video data or any other data that changes over time during use of the catheter system 100. In various embodiments, the GUI 127 can include one or more colors, different sizes, varying brightness, etc., that may act as alerts to the user or operator. Additionally, or in the alternative, the GUI 127 can provide audio data or information to the user or operator. It is appreciated that the specifics of the GUI 127 can vary depending upon the design requirements of the catheter system 100, or the specific needs, specifications and/or desires of the user or operator.

As shown in FIG. 1 , the handle assembly 128 can be positioned at or near the proximal portion 114 of the catheter system 100, and/or near the source manifold 136. In this embodiment, the handle assembly 128 is coupled to the balloon 104 and is positioned spaced apart from the balloon 104. Alternatively, the handle assembly 128 can be positioned at another suitable location.

The handle assembly 128 is handled and used by the user or operator to operate, position and control the catheter 102. The design and specific features of the handle assembly 128 can vary to suit the design requirements of the catheter system 100. In the embodiment illustrated in FIG. 1 , the handle assembly 128 is separate from, but in electrical and/or fluid communication with one or more of the system controller 126, the energy source 124, the fluid pump 138, and the GUI 127. In some embodiments, the handle assembly 128 can integrate and/or include at least a portion of the system controller 126 within an interior of the handle assembly 128. For example, as shown, in certain such embodiments, the handle assembly 128 can include circuitry 156 that can form at least a portion of the system controller 126. In one embodiment, the circuitry 156 can include a printed circuit board having one or more integrated circuits, or any other suitable circuitry. In an alternative embodiment, the circuitry 156 can be omitted, or can be included within the system controller 126, which in various embodiments can be positioned outside of the handle assembly 128, e.g., within the system console 123. It is understood that the handle assembly 128 can include fewer or additional components than those specifically illustrated and described herein.

FIG. 2A is a schematic cross-sectional view of a portion of an embodiment of the catheter system 200. The design of the catheter system 200 can be varied. In various embodiments, as illustrated in FIG. 2A, the catheter system 200 can include a catheter 202 including a catheter shaft 210, a balloon 204 including a balloon wall 230 that defines a balloon interior 246, a balloon proximal end 204P, and a balloon distal end 204D, a balloon fluid 232 that is retained substantially within the balloon interior 246, and a guidewire lumen 218 that extends into and/or through the balloon interior 246; and an energy guide 222A. Alternatively, in other embodiments, the catheter system 200 can include more components or fewer components than what is specifically illustrated and described herein. For example, certain components that were illustrated in FIG. 1 , e.g., the guidewire 112, the source manifold 136, the fluid pump 138, the energy source 124, the power source 125, the system controller 126, the GUI 127, and the handle assembly 128, are not specifically illustrated in FIG. 2A, but could be included in any embodiment of the catheter system 200.

Similar to previous embodiments, the balloon 204 is selectively movable or inflatable between a deflated state suitable for advancing the catheter 202 through a patient's vasculature, and an inflated state (such as shown in FIG. 2A) suitable for anchoring the catheter 202 in position relative to the treatment site 106 (illustrated in FIG. 1 ). Additionally, as shown in this embodiment, the balloon 204 is asymmetrical such that the balloon 204 includes a balloon central axis 260 when the balloon 204 is in the inflated state, and the balloon proximal end 204P and the balloon distal end 204D define a balloon end axis 262 that is different than and offset from the balloon central axis 260. Stated in another manner, the balloon central axis 260 extends through a geometric center 204C of the balloon 204 (and parallel to a length of the balloon 204 from the balloon proximal end 204P to the balloon distal end 204D) when the balloon 204 is in the inflated state, and the balloon end axis 262 extends centrally through the balloon proximal end 204P and the balloon distal end 204D. As utilized herein, the “geometric center” of the balloon 204 is a point or area that is substantially equidistant from a first wall side 230A and a second wall side 230B of the balloon wall 230 and in all radial directions extending directly (i.e. the shortest distance) toward the balloon wall 230, and substantially equidistant from the balloon proximal end 204P and the balloon distal end 204D.

In some embodiments, the balloon end axis 262 can be substantially coaxial with the longitudinal axis 144 (illustrated in FIG. 1 ) of the catheter shaft 210. Additionally, in certain embodiments, the balloon end axis 262 is spaced apart from and substantially parallel to the balloon central axis 260.

The balloon 204 has a balloon radius 204R, which is measured from the geometric center 204C of the balloon 204 directly (i.e. the shortest distance) to the balloon wall 230. In designing the asymmetric shape of the balloon 204, in various embodiments, it is desired that the balloon end axis 262 be spaced apart from the balloon central axis 260 by at least a certain axis spacing distance 264 (also referred to simply as a “spacing distance”) measured relative to the balloon radius 204R. For example, in certain non-exclusive embodiments, the balloon end axis 262 is spaced apart from the balloon central axis 260 by the spacing distance 264 of between at least approximately one percent (1%) and less than approximately ninety percent (90%) of the balloon radius 204R. In various non-exclusive alternative embodiments, the balloon end axis 262 can be spaced apart from the balloon central axis 260 by the spacing distance 264 of at least approximately 2%, 3%, 4%, 5%, 7%, 8%, 10%, 12%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80% or 85% of the balloon radius 204R. By way of a specific non-limiting example, if the balloon radius 204R of the balloon 204 is five millimeters (balloon diameter is ten millimeters), providing a spacing distance 264 between the balloon end axis 262 and the balloon central axis 260 of 5% of the balloon radius 204R, would result in the spacing distance 264 between the balloon end axis 262 and the balloon central axis 260 being 5 mm×0.05=0.25 millimeters (or 250 μm). As illustrated in FIG. 2A, the balloon 204 includes (i) a first wall distance 230X between the first wall side 230A and the energy guide 222A, and (ii) a second wall distance 230Y between the second wall side 230B and the guidewire lumen 218.

The balloon catheter 202, e.g., a laser-driven intravascular lithotripsy balloon catheter, includes one or more energy guides 222A that deliver pulsed energy from an energy source 124 (illustrated in FIG. 1 ) to the balloon fluid 232 that fills the balloon interior 246 of the balloon 204. The pulsed energy creates localized plasma that in turn generates an acoustic bubble 134 (illustrated in FIG. 1 ) and pressure waves that impinge on the balloon wall 230 of the balloon 204. The therapeutic effect is achieved by mechanical energy imparted through the balloon walls 230 that breaks intravascular lesions 106A (illustrated in FIG. 1 ) at the treatment site 106 (illustrated in FIG. 1 ). However, it is appreciated that it is an advantage to generate the plasma uniformly relative to the balloon wall 230 and/or as far away from the balloon wall 230 as possible to reduce the probability of device malfunctions, such as balloon rupture caused by the high-temperature plasma melting the balloon wall 230. Positioning at least the guide distal end 222D of the energy guide 222A as close as possible to, or precisely on, the balloon central axis 260 provides the greatest distance between the plasma and the balloon wall 230, while also providing uniformity of plasma generation relative to the balloon wall 230.

One way to place the guide distal end 222D on or near the inflated balloon central axis 260 is to offset the guidewire lumen 218 from the balloon central axis 260 of the inflated balloon 204. In various embodiments, moving the guidewire lumen 218 off the balloon central axis 260 can be achieved by forming the asymmetric balloon shape, where the balloon ends 204P, 204D define the balloon end axis 262 that is different than the balloon central axis 260 of the inflated balloon 204, as shown in FIG. 2A.

In the embodiment illustrated in FIG. 2A, the guidewire lumen 218 is positioned substantially along the balloon end axis 262, and at least a portion of the energy guide 222A, including the guide distal end 222D, is positioned substantially adjacent to the guidewire lumen 218 and substantially on the balloon central axis 260. Stated in another manner, the guidewire lumen 218 is offset from the balloon central axis 260 and at least a portion of the energy guide 222A, including the guide distal end 222D, is positioned on the balloon central axis 260. It is appreciated that the advantage of this configuration is that it allows for the guide distal end 222D of the energy guide 222A from which the plasma is generated to be centered on the balloon central axis 260. This allows for a more uniform pressure wave application to the balloon wall 230, and thus the vascular lesion 106A at the treatment site 106, since at least the guide distal end 222D of the energy guide 222A (at or near where the plasma generation occurs) is located equidistant from the balloon wall 230 around the circumference of the balloon 204.

It is appreciated that the energy guide 222A need not be positioned substantially directly adjacent to and/or abutting the guidewire lumen 218, and/or be secured to the guidewire lumen 218. However, it is desired that at least the guide distal end 222D of the energy guide 222A be positioned on the balloon central axis 260. For example, in one non-exclusive alternative embodiment, the energy guide 222A can be positioned spaced apart from the guidewire lumen 218, while at least a portion of the energy guide 222A including the guide distal end 222D is still being positioned on the balloon central axis 260.

As illustrated in FIG. 2A, in some embodiments, the balloon proximal end 204P can be coupled to the catheter shaft 210 and the balloon distal end 204D can be coupled to the guidewire lumen 218. The balloon 204 can be inflated with the balloon fluid 232, e.g., from the fluid pump 138 (illustrated in FIG. 1 ), that is directed into the balloon interior 246 of the balloon 204 via the inflation conduit 140 (illustrated in FIG. 1 ).

The energy guide 222A can guide energy from the energy source 124 along its length to the guide distal end 222D. The energy guide 222A can have at least one guide window (not shown) that is positioned along a length of the energy guide 222A within the balloon interior 246 of the balloon 204.

In certain embodiments, the energy guide 222A can include one or more photoacoustic transducers 254, where each photoacoustic transducer 254 can be in optical communication with the energy guide 222A within which it is disposed. In some embodiments, the photoacoustic transducers 254 can be in optical communication with the guide distal end 222D of the energy guide 222A. The photoacoustic transducer 254 is configured to convert light energy into an acoustic wave at or near the guide distal end 222D of the energy guide 222A. The direction of the acoustic wave can be tailored by changing an angle of the guide distal end 222D of the energy guide 222A.

The energy guide 222A can also include one or more diverting features or “diverters” (not shown in FIG. 2A) within the energy guide 222A that are configured to direct energy to exit the energy guide 222A toward a side surface that can be positioned at or near the guide distal end 222D of the energy guide 222A, and toward the balloon wall 230. The energy guide 222A can also include one or more guide windows disposed along the longitudinal or axial surfaces of the energy guide 222A and in optical communication with a diverting feature. Stated in another manner, the diverting features can be configured to direct energy in the energy guide 222A toward a side surface that is positioned at or near the guide distal end 222D, where the side surface is in optical communication with a guide window. Upon contact with the diverting feature, the energy is diverted within the energy guide 222A to the photoacoustic transducer 254 that is in optical communication with a side surface of the energy guide 222A. Similar to previous embodiments, the photoacoustic transducer 254 then converts light energy into an acoustic wave that extends away from the side surface of the energy guide 222A.

FIG. 2B is a schematic cross-sectional view of the portion of the catheter system 200 taken on line B-B in FIG. 2A. In particular, FIG. 2B illustrates a cross-sectional view of the balloon 204, the guidewire lumen 218 and the energy guide 222A that are included as part of the catheter system 200. As illustrated in FIG. 2B, at least the guide distal end 222D of the energy guide 222A is positioned on, along or about the balloon central axis 260 (illustrated in FIG. 2A) of the balloon 204 when the balloon 204 is in the inflated state. FIG. 2B also shows that the guidewire lumen 218 is positioned offset from the balloon central axis 260 when the balloon 204 is in the inflated state.

FIG. 2C is a schematic cross-sectional view of the portion of the catheter system 200 taken on line C-C in FIG. 2A. In particular, FIG. 2C illustrates a cross-sectional view of the balloon 204 at the balloon proximal end 204P, the catheter shaft 210, the guidewire lumen 218 and the energy guide 222A that are included as part of the catheter system 200. As illustrated in the embodiment illustrated in FIG. 2C, the guidewire lumen is positioned on, coaxially with or about the balloon end axis 262 (illustrated in FIG. 2A) of the balloon 204 when the balloon 204 is in the inflated state. FIG. 2C also illustrates that the energy guide 222A is positioned offset from the balloon end axis 262 when the balloon 204 is in the inflated state.

FIG. 3 is a schematic cross-sectional view of a portion of another embodiment of the catheter system 300. The catheter system 300 can include any desired number of energy guides. In particular, FIG. 3 illustrates a cross-sectional view of a balloon 304, a guidewire lumen 318, a first energy guide 322A and a second energy guide 322B. It is appreciated that in catheter systems 300 including more than one energy guide, the energy guides can be disposed at any suitable positions about the circumference of the guidewire lumen 318 and/or the catheter shaft (not shown in FIG. 3 ). For example, in the embodiment shown in FIG. 3 which includes two energy guides 322A, 322B, the first energy guide 322A and the second energy guide 322B can be separated or spaced apart by approximately 180 degrees from one another about the circumference of the guidewire lumen 318.

In embodiments that include two or more energy guides, at least a portion of one of the energy guides 322A, including the guide distal end 322D, is positioned on the balloon central axis 260, as illustrated in FIG. 3 . For example, in the embodiment illustrated in FIG. 3 , at least the guide distal end 322D of the first energy guide 322A is positioned on the balloon central axis 260, the guidewire lumen 318 is positioned offset from the balloon central axis 260, and the second energy guide 322B is positioned substantially opposite to the first energy guide 322A about the circumference of the guidewire lumen 318. Stated in another manner, the second energy guide 322B is separated from the first energy guide 322A by approximately 180 degrees about the circumference of the guidewire lumen 318. With such design, the guide distal end 322D of the first energy guide 322A being positioned on the balloon central axis 260 allows for a more uniform pressure wave application to the balloon wall 330, and thus the vascular lesion 106A (illustrated in FIG. 1 ) at the treatment site 106 (illustrated in FIG. 1 ), since the guide distal end 322D of the first energy guide 322A is located at equal distances from the balloon wall 330 all the way around the balloon 304. The second energy guide 322B can allow for additional pressure wave application to portions of the balloon wall 330 that may have been otherwise blocked from the pressure wave application from the first energy guide 322A due to the presence and positioning of the guidewire lumen 318.

It is appreciated that the energy guides 322A, 322B can be disposed uniformly or non-uniformly about the guidewire lumen 318 and/or the catheter shaft to achieve the desired effect in the desired locations. It is further recognized that the energy from the energy source 124 (illustrated in FIG. 1 ) can be different for each of the energy guides 322A, 322B. For example, in one non-exclusive embodiment, the energy source 124 can direct a higher level of energy to the first energy guide 322A to provide a majority of the pressure wave that is ultimately applied to the balloon wall 330 (and thus the vascular lesions 106A at the treatment site 106), and a lower level of energy to the second energy guide 322B to provide supplemental pressure wave application to a portion of the balloon wall 330 that was blocked from receiving such pressure waves from the first energy guide 332A due to the presence and positioning of the guidewire lumen 318.

It should be noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content and/or context clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content or context clearly dictates otherwise.

It should also be noted that, as used in this specification and the appended claims, the phrase “configured” describes a system, apparatus, or other structure that is constructed or configured to perform a particular task or adopt a particular configuration. The phrase “configured” can be used interchangeably with other similar phrases such as arranged and configured, constructed and arranged, constructed, manufactured and arranged, and the like.

The headings used herein are provided for consistency with suggestions under 37 CFR 1.77 or otherwise to provide organizational cues. These headings shall not be viewed to limit or characterize the invention(s) set out in any claims that may issue from this disclosure. As an example, a description of a technology in the “Background” is not an admission that technology is prior art to any invention(s) in this disclosure. Neither is the “Summary” or “Abstract” to be considered as a characterization of the invention(s) set forth in issued claims.

The embodiments described herein are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art can appreciate and understand the principles and practices. As such, aspects have been described with reference to various specific and preferred embodiments and techniques. However, it should be understood that many variations and modifications may be made while remaining within the spirit and scope herein.

It is understood that although a number of different embodiments of the catheter system have been illustrated and described herein, one or more features of any one embodiment can be combined with one or more features of one or more of the other embodiments, provided that such combination satisfies the intent of the present invention.

While a number of exemplary aspects and embodiments of the catheter system have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations thereof. It is therefore intended that the following appended claims and claims hereafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations as are within their true spirit and scope, and no limitations are intended to the details of construction or design herein shown. 

What is claimed is:
 1. A catheter system for treating a treatment site within or adjacent to a vessel wall within a body of a patient, the catheter system comprising: an energy source that generates energy; a balloon including a balloon wall that defines a balloon interior, the balloon being configured to retain a balloon fluid within the balloon interior, the balloon being selectively inflatable with the balloon fluid to expand to an inflated state wherein the balloon wall is positionable substantially adjacent to the treatment site, the balloon having a balloon central axis that extends through a geometric center of the balloon when the balloon is in the inflated state; and a plurality of energy guides that selectively receive energy from the energy source, each of the plurality of energy guides guiding the energy from the energy source into the balloon interior, each of the plurality of energy guides including a guide distal end; wherein at least a portion of the guide distal end of a first energy guide of the plurality of energy guides is positioned on the balloon central axis when the balloon is in the inflated state; and wherein each of the plurality of energy guides receives the energy from the energy source and guides the energy from the energy source into the balloon interior to generate plasma in the balloon fluid within the balloon interior, the plasma generation causing rapid bubble formation and imparting pressure waves upon the balloon wall adjacent to the treatment site.
 2. A catheter system for treating a treatment site within or adjacent to a vessel wall within a body of a patient, the catheter system comprising: an energy source that generates energy; an asymmetrical balloon including a balloon wall that defines a balloon interior, the balloon being configured to retain a balloon fluid within the balloon interior, the balloon being selectively inflatable with the balloon fluid to expand to an inflated state wherein the balloon wall is positionable substantially adjacent to the treatment site, the balloon further including (i) a balloon proximal end, (ii) an opposed balloon distal end, (iii) a balloon end axis that extends through the balloon proximal end and the balloon distal end when the balloon is in the inflated state, and (iv) a balloon central axis that extends through a geometric center of the balloon when the balloon is in the inflated state, the balloon central axis being spaced apart from and substantially parallel to the balloon end axis, the balloon having a balloon radius, the balloon central axis being spaced apart from the balloon end axis by an axis spacing distance of at least approximately five percent of the balloon radius; and an energy guide that selectively receives energy from the energy source, the energy guide guiding the energy from the energy source into the balloon interior, wherein the energy guide includes a guide distal end; wherein no portion of the guide distal end that is positioned on the balloon central axis when the balloon is in the inflated state; and wherein the energy guide receives the energy from the energy source and guides the energy from the energy source into the balloon interior to generate plasma in the balloon fluid within the balloon interior; and wherein the plasma generation causes rapid bubble formation and imparts pressure waves upon the balloon wall adjacent to the treatment site.
 3. The catheter system of claim 2 further comprising a guidewire lumen that extends at least between the balloon proximal end and the balloon distal end, the guidewire lumen being positioned offset from the balloon central axis.
 4. The catheter system of claim 3 wherein the guidewire lumen is positioned substantially along the balloon end axis.
 5. The catheter system of claim 2 further comprising a catheter shaft, wherein the balloon is coupled to the catheter shaft.
 6. The catheter system of claim 5 wherein the catheter shaft includes a longitudinal axis, and wherein the longitudinal axis is substantially coaxial with the balloon end axis.
 7. The catheter system of claim 2 wherein the energy guide includes an optical fiber.
 8. The catheter system of claim 2 wherein the energy source is a laser source that provides pulses of laser energy.
 9. A catheter system for treating a treatment site within or adjacent to a vessel wall within a body of a patient, the catheter system comprising: an energy source that generates energy; an asymmetrical balloon including a balloon wall that defines a balloon interior, the balloon being configured to retain a balloon fluid within the balloon interior, the balloon being selectively inflatable with the balloon fluid to expand to an inflated state wherein the balloon wall is configured to be positioned substantially adjacent to the treatment site, the balloon further including (i) a balloon proximal end, (ii) an opposed balloon distal end, (iii) a balloon end axis that extends through the balloon proximal end and the balloon distal end when the balloon is in the inflated state, and (iv) a balloon central axis that extends through a geometric center of the balloon when the balloon is in the inflated state, the balloon central axis being spaced apart from and substantially parallel to the balloon end axis; a guidewire lumen that extends between the balloon proximal end and the balloon distal end, the guidewire lumen being positioned substantially along the balloon end axis and offset from the balloon central axis; a catheter shaft including a longitudinal axis that is substantially coaxial with the balloon end axis, the balloon being coupled to the catheter shaft; a first energy guide that selectively receives energy from the energy source and guides the energy into the balloon interior to generate plasma in the balloon fluid within the balloon interior, the plasma generation causing rapid bubble formation and imparting pressure waves upon the balloon wall adjacent to the treatment site, the first energy guide including a first guide distal end; and a second energy guide that selectively receives energy from the energy source and guides the energy into the balloon interior to generate plasma in the balloon fluid within the balloon interior, the plasma generation causing rapid bubble formation and imparting pressure waves upon the balloon wall adjacent to the treatment site, the second energy guide including a second guide distal end; wherein at least a portion of the first guide distal end of the first energy guide is positioned on the balloon central axis when the balloon is in the inflated state; and wherein no portion of the second guide distal end of the second energy guide is positioned on the balloon central axis when the balloon is in the inflated state.
 10. The catheter system of claim 1 wherein each of the plurality of energy guides includes an electrode pair including spaced apart electrodes that extend into the balloon interior; and wherein pulses of high voltage from the energy source are applied to the electrodes and form an electrical arc across the electrodes.
 11. The catheter system of claim 1 wherein the balloon further includes a balloon proximal end, an opposed balloon distal end, and a balloon end axis that extends through the balloon proximal end and the balloon distal end when the balloon is in the inflated state, the balloon end axis being offset from the balloon central axis.
 12. The catheter system of claim 1 wherein the balloon is asymmetrical in the inflated state.
 13. The catheter system of claim 9 wherein each of the first energy guide and the second energy guide includes an optical fiber and the energy source is a laser source that provides pulses of laser energy.
 14. The catheter system of claim 9 wherein each of the first energy guide and the second energy guide includes an electrode pair including spaced apart electrodes that extend into the balloon interior; and wherein pulses of high voltage from the energy source are applied to the electrodes and form an electrical arc across the electrodes.
 15. The catheter system of claim 1 wherein no portion of the guide distal end of a second energy guide of the plurality of energy guides is positioned on the balloon central axis when the balloon is in the inflated state.
 16. The catheter system of claim 1 wherein each of the plurality of energy guides includes an optical fiber; and wherein the energy source is a laser source that provides pulses of laser energy.
 17. The catheter system of claim 11 further comprising a guidewire lumen that extends at least between the balloon proximal end and the balloon distal end, the guidewire lumen being positioned offset from the balloon central axis and substantially along the balloon end axis.
 18. The catheter system of claim 11 further comprising a catheter shaft including a longitudinal axis; wherein the balloon is coupled to the catheter shaft; and wherein the longitudinal axis is substantially coaxial with the balloon end axis.
 19. The catheter system of claim 2 further comprising a second energy guide that selectively receives energy from the energy source and guides the energy into the balloon interior to generate plasma in the balloon fluid within the balloon interior, the plasma generation causing rapid bubble formation and imparting pressure waves upon the balloon wall adjacent to the treatment site, the second energy guide including a second guide distal end; wherein at least a portion of the second guide distal end of the second energy guide is positioned on the balloon central axis when the balloon is in the inflated state.
 20. The catheter system of claim 2 wherein the energy guide includes an electrode pair including spaced apart electrodes that extend into the balloon interior; and wherein pulses of high voltage from the energy source are applied to the electrodes and form an electrical arc across the electrodes. 